Means for guiding, floating, and cementing well casing in bored holes



S. B. SCHNITTER MEANS FOR GUIDING, FLOATING, AND CEMENTING WELL CASINGIN BORED HOLES Dec. l5, 1953 2 Sheets-Sheet l Filed June 27, 1947ttorneg Dec. 15, 1953 s. B. scHNlTTl-:R 2,662,602

MEANS FOR GUIDING, FLOTING, AND CEMENTING WELL CASING IN BORED HOLESFiled June 27, 1947 2 Sheets-Sheet 2 Snoentor Gttorncg Patented Dec. l5,1953 MEANS FOR GUIDING, FLOATING, AND CE- MENTING WELL CASIN G IN BOREDHOLES Sylvester B. Schnitter, Dallas, Tex., assignor to L. L. Rector,Tarrant County, Tex.

Application June Z7, 1947, Serial No. 757,452

(Cl. 16B- 1) 10 Claims. l

This application is concerned with means for guiding, oating andcementing well casing in bored holes; and it is particularly concernedwith improvements in means to overcome the tendency to channel thecementing slurry through the Well uid and further to prevent the mixtureof the cementing slurry with the well iiuid in the well pipe during thecen/renting operation.

Through the use of my invention, I have minimized the hazard ofpermitting inud cake deposits to remain in the Well bore, by providing agreater volume iiow` from the well casing to the well bore for washpurposes.

My invention eliminates the great expense entailed under the oldpractices, in that it is new unnecessary to use special pumpingequipment in order to attain the required volume ilow through thecasing, as is done with the prior methods and devices. Through the useof my invention I eliminate the aforesaid flow restrictions in thecasing, such as have been used in the prior devices.

In my invention, where it is necessary to have a restriction in thecasing to perform the functions of such restrictions in the casings ashave appeared in prior devices, I have provided a Venturi form of iiowpassageway.

By using the Venturi form of ow passage I have incorporated thefollowing principle: When iiuid flows through a venturi its velocityrapidly increases from its entrance to the throat of the venturi, anddecreases from the throat of the venturi to its outlet. The pressure isgreatest at the entrance to the venturi, and at the outlet, and is leastat its throat. The pressure lost at the throat of the venturi is almostentirely regained at its outlet. rthus, by passing the fluid through aVenturi-like pasu sage in the casing, almost the same amount of iiuidwill be delivered through the well conduit, without increasing thepressure on the pumping equipment. This Venturi principle of flowpassageway inside a well casing, during a cemen'ting operation, has notbeen used in the prior methods and devices for guiding and/or floatingand/or cernenting Well casing in bored holes.

It is desirable that all duide employed during a well cenientingoperation must be segregated from each other so far as it is possible toeffect V such separation.

Such segregation of iuids can only be accomplished within the well pipe.My means as disclosed herein provide for segregaton of iiuids throughoutthe full length oi the pipe. My

means accomplishes a positive segregation between the fluids in thepipe; and no nuids pass through the segregating means, and substantiallyno fluids pass around them. Thus, I have, by the use of my means,eliminated the causes which generate the cement-mud ball mass formed inthe casing in prior well cementing practice. This is of greatimportance.

In the use of small criiice ttings in the casing in prior devices usedin cementing wells, as above described, the formation of cement-mudballs in the casing necessitated increased pumping pressure in order toforce the mass formed by the cement-mud balls through the oricelikerestrictions. By eliminating the formation ci the cement-mud balls inthe casing in the use of my device, I can and do utilize the ordinarypumping equipment customarily used in well drilling practice. Thisresults in extensive economies and much savings in equipment and costs.

By providing the means of my invention for segregating the well uids,the wash water is discharged from the well pipe in a free state, and thecementing slurry is likewise discharged from the well pipe in anuncontaminated state. Thus, the greatest possible benefit is derivedfrom the wash Water and cementing slurry.

In prior cementing operations it has been the practice to disjoint thecementing head or surface fittings from the casing in order to injectthe old style segregating means used as spacers between the fluids inthe casing. The result of this practice has been that, while the surfacettings are disconnected, air is allowed to enter the casing. When thisresult occurs after the coniinng of the cementing slurry in the casing,the cementing slurry (being of greater density than the well iiuid aheadof it) will displace the well fluid and a void will be left at the topof the column of slurry. When the well head iitting is replaced, airwill then be trapped in the void thus formed between the plug insertedand the cementing slurry. Thus, the air will be trapped between thecolumn of iiuid below the plug and the column of uid above the plug.When pressure is applied to the plug above this ai pocket, the air,being of less density and viscosity than the cementing slurry ahead ofit, will be compressed and will permeate into the cementing slurry andcause the formation of pockets or honeycomb-like recesses within theslurry, and thus weaken it. This is a most undesirable result fraughtwith grave consequences.

By the use of my device, I have overcome the introduction or air intothe bore of the well pipe by induct.- all segregating means, desired foruse in a cej enting operation, into the casing, under pressure, whilethe pump is in operation, and thus causing no stop-page of the flowstream. No voids result.

Among the objects to be attained by my invention are those indicated inthe foregoing dissertation, and also the following:

l. To provide means for the floating and guiding of a string of casinginto a well bore and to the desired level for the purpose o cementingthe casing in the well bore.

2. To provide disengageable means within the casing which may bedislodged by other means so as tc provide substantially full casing areaflow through the well pipe after the casing has been run to the desiredlevel in the well bore.

3. To provide maximum area inside the well pipe for the iiow of nuidtherethrough so as to reduce the well pumping pressure required and toincrease the volume of flow of fluid through the weil circulatingcircuit.

4.. To provide and make effective the segre'fation of all iiuids in thewell pipe during a cementing operation.

5. To provide valve means which move with the flow stream in the wellpipe and operate to prevent the discharging of fluid from the well pipe,when desired; and such means further preventing the idowback of fluidinto the well pipe after the discharge of the duid from the well pipehas taken place.

6. To provide a rigid segregating for segregating the fluids in the wellpipe, which means has the capability of being deformed and reformed tothe contour of the bore or passage- Way through the well pipe.

'7. To provide means for inducting all segre gating spacer means intothe flow stream, inside the casing, while the casing is under pressure,and without interrupting the iiow oi iiuid through the well now circuit,during a cementing operation.

Other and further objects of my invention will become apparent upon thereading of the detailed specification which follows hereinafter.

My method and means for guiding, oating and cementing well casing inbored holes, and a suitable arrangement and construction of the partethereof, and their operation and use, are illustrated in theaccompanying drawings, which disclose a satisfactory and preferred formor my device.

It is to be understood, however, that I can practice my inventioneffectively and satisfactorily with various devices which incorporateuse the same, notwithstanding that such devices may be in forms andarrangements som what different from the structuresillustrated in theaccompanying drawings; and such departure from the structures delineatedherein will not depart from the spirit and essential principles o myinvention.

In the drawings:

Fig. I is a partially sectionalized elevation show ing several levels ina typical well about to be cemented, wherein my oat shoe and stallcollar are carried by the casing in position in the bore hole, andwherein the cementing head is connected to the top of the casing abovethe earths snrface.

Fig. II is a partially sectionalized elevation. of certain levels of atypical well at the time or dislodging my float assembly from the iloatshoe by pressure operated trip means, and wherein a primary collapsiblespacer plug is positioned in the cement head prior to its introductioninto the well casing.

Fig. III is a partially sectionalized elevation ci a typical well with avolume of cementing slurry conned in the casing between a primarycollapsible spacer plug and a top collapsible spacer plug, which latterplug carries a check valve.

Fig. IV is a partially sectionalized elevation oi a typical well whereinmy cementing apparatus has been employed and wherein a volume of slur ryfor cementing the casing in the bored hole has been discharged from thecasing into the well bore, and wherein a check valve prevents furthermovement of fluids in the casing.

Fig. V is a partially sectionalized elevation my float shoe carried byand below the weil pipe, and wherein the shoe assembly trip ball isshown in the well pipe near its seating position.

Fig. VI is a partially scctionalized elevation oi my stall collar,connected above and below to the well casing, and or" my collapsiblespacer plug, and of check valve.

Fig. VII is a partially sectionalized elevation of the upper portion ofmy cement head having an adapting liner positioned therein, and of mytop collapsible spacer plug, and oi my check valve.

In the drawings, the various parts and elements of structures employedin the practice of my invention, and in the construction and op erationof devices required thereby, are indicated by numerals; and numeral lindicates the earths strata; and numeral 2 identies the lbore of a well,whether it be an oil well, a gas well, a water well or other type oiWell. In Fig. I the well casing 3 has been guided and floated into thedrilled hole to the desired depth.

In Fig. I the typical well casing 3 carries the float shoe d, in whichthe float assembly l5 is positioned. A valve in the neat assembly i5 isa b-acls pressure check valve of a type such as has been heretofore usedin floating and guiding Well casing into bored holes. In thisconstruction well fluid may flow downwardly through the float shoe, butthe lluid is prevented from flowing back into the casing through thefloat shoe.

During the time that the casing is being guided into the well bore bythe defiecting action of the rounded sides of the shoe guide Ita, thewell pipe acquires a 'floating buoya cy. The buoyant ball i8 inside thefloat assembly l5, is floated upward from its seat ld because thepressure of the fluid head on the outside of the casing is greater thanthe pressure of the iiuid head on the inside of the casing. The floatball l5 is retained within the float assembly l5 by means of rests orarms ita, which also form a seat for the ball, and such arms may be madeintegral with the float assembly l5.

In this float assembly 25 the valve ball it is caused to iioat duringthe time the casing is being guided into the well bore by reason of thefact that the speciiic gravity of valve ball t8 is less than thespeciiic gravity of the well fluid. The area of the opening ib throughwhich fluid may be discharged during the guiding and floating period ismuch smaller than the area of the bore of the casing. Consequently, byapplying pres- .sure to the top of the casing, iiuid can be caused todischarge through the opening |312 in jet-like fashion, since the fluidis being forced from a large area through a small area. This effect isuseful during the guiding and floating period. Should the casingencounter mud bridges or other mov 5 able restrictions in the well boreon its progress downward, liuid may be jetted through the opening ith,by puinp pressure from above so a's to wesh away the bridges or otherrestrictions.

A typical string of casing 3 also carries the stall collar li, which isplaced on the casing above 'the float shoe il, at the desired level inthe hole. 'The spaced relation between the stall collar 5 and the shoefl of course determines the amount ci" cement-ing slur-ry to remainwithin the bore of the casing after the cementing operation iscompleted; and in norrnal practice such spacing customarily will 'notexceed 100 feet. This spaced relation between the stall collar and theshoe is determined by the choice of the operator.

Also pcsiticnedon the string of casing 3 is a cement head 5, which isdisposed at the top ol' the casing above the earths surface. The cementhead t and its appurtenant connections constitute the connecting meansbetween the surface well pumps and the casing. By this cement headarrangement and connection, fluid may be pumped from the usual surfacestorage facilities, downwardly through the bore E of the casing, fordischarge through the float shoe d into the bore 2 oi the well, andthence be directed upwardly behind the casing and returned to the saidsurface storage facilities. This entire ilow passageway, as abovedescribed, is commonly known as the well iiow circuit.

In this well flow circuit, a connecting fluid line 5e is caused tocommunicate with the cement head, and the bore of the casing by joinderto one opening or" the cross T53. The cross T9 is threade'ily connectedto the top of the casing and fitted below the standard commercial plugvalve l. The other Sc of cross TQ is shown in the drawings as beingplugged, but such opening is adapted to receive connection with a conduit from the surface pumps if such connection be desired.

At the top or the cement head li is connected one end or" the flexiblehose lil, the other end of which lexible hose is caused to communicatewith the fluid line Se through valve l2, TIS and valve l i. 'Elexiblehose it? also communicates with flow line i3d which is in turn connectedto the surface pumps (not shown).

By this arrangement or manifold valves connected between the surfacehumos and the cen inenting head and casing, the flow of fluid into thecasing can be directed and controlled. The when valve l i is in openposition., while the coin inercial plug valve and valve l2 on the fleaole hose line are in closed position, the :duid pumped from the surfacepumps is delivered to the bore of the casing without passing through thece ment However, when valve l2 on the hex ible hose line, and commercialplug valve l, are in open position, while valve Il is in a closedposition, the fluid pumped from the surn face pumps through flow linei3d is delivered to the bore of the casing by passing through the cementhead. This flow control arrangement is an important part of niinvention, as will be demonstrated later in this specification.

While the assembly is positioned as shown in Fig. l, it may be desirableto wash and the well flow circuit, which is customary practice, beforethe cernenting operation. This done by manipulating the valvearrangement on the ceinenting head so that the well washing fluid willnot pass through the cernenting head during this washing period, butwill flow di rectly into the casing.

However, before the well washing operation begins the l'oat assembly l5is dislodged from the float shoe fl so that there will be no restriction in the float shoe during this operation. This is done by manuallydropping the iloat shoe trip ball it into the bore of the well casingbefore the cement head t is placed into position thereon. rhis trip ballit, having a spen cie gravity greater than the well fluid, willgravitate to the bottom of the well casing bore until it reaches aclosure seat il in the float assembly l5 of the float shoe rlihe closureseat Il is constructed or a tubular member having upper and lowertapered surfaces lla and llo respectively. The tubular member il isremovably mounted in assembly lll by means of threads 45a. Taper ilaprovides a seat for trip ball itl. Taper lib provides a seat for floatball i8, while the casing is being floated into the well `riore toprevent baclziiow of fluid into the casing.

To facilitate the movement or trip ball it to its seating position itmay be hastened in its progress to the bottom of the well casing byapplying pump pressure to the casing through proper connections to thecasing.

There is a plurality or" shearing screws le, passing through the wall ofthe tubular body 2S of the float shoe e, and into the wall of the oatassembly i5, so that assembly Eli is frangibly mounted in the shoe.After the trip ball IS has fornd lodgment on taper llc of closure seatIl, hydraulic pressure is applied by the surface pumps to the bore or"the casing to such an extent that the pressure applied to the trip balll5 and assembly le will fracture the shearing screws i9 which permitsthe dislodgment and movement of the neat assembly downwardly in the body2B and thus causes its ejection from the shoe into the bore of the well.

Were the float assembly l5 not elected from the oat 'shoe e, the ow offluid through the well casing bore l would be greatly restricted,because it is obvious that the passage ich is much smaller in crosssectional area than the bore of the casing. However, after ejectingfloat assembly l5 from the oat shoe in the manner above described, thearea of opening within the shoe through which the fluid is per mitted toiiow is substantially the same as the area in the well pipe.Consequentl', the volume of how through the unrestricted casing boreafter electing the oat assembly is also greatly increased.

The oat assembly i5 is shown as partially dislodged in Fie. II by theaction of pressure applied to the trip ball Eli, as above described.Float assembly i5 and tripping ball U5, L of greater specic gravity thanthe well f. will fall downwardly in the well bore after theirdislodgrnent, as shown in Figures Ill and El?. Float assembly i5 andtrip ball le are made of drillable material, which may be later drilledup, should the well drilling operation be carried to a depth beyond theinitial subsurface positioning of the well pipe which cerneni d.

The float assembly and tripping ball made 'of aluminum, magnesium,plastic or a combination of same, or other materie drillablecharacteristic. By the ter. di is meant that these elements may be cutby the drill bit, along with any cement or materials around there.'after the cernenting .ich is finished. Such drilling may be ecessary inorder to provide a free and unobstructed passageway for the guiding andfloating of a subsequent well pipe that may be later cemented in adeepened well bore. v

My invention, therefore, provides a well pipe bore which is free of allsemi-closed iiow restrictions. It provides a free and unobstructedconduit or passageway for the movement oi cementing slurry or otheriluids; and such passageway is substantially the same in cross sectionalarea as the bore of the casing.

After the well ow circuit has been Wash-circulated to the satisfaction ithe operator, the collapsible plug Hl is placed in the cementing headEi, as shown in Fig. II. This fluid segregating collapsible plug, andall subsequent uid segregating coilapsible plugs desired to be infectedinto the well casing, are positioned in the cementinor head Withoutinterrupting the flow stream through the well circuit. Therefore, theintroduction oi such plugs does not require the releasing of thepressure of the circulating pumps.

The plugs be positioned above the casing for introduction thereto bysimply removing the hood or bonnet 2i from the cement head. The removalof the hood 2i may be accomplished by the withdrawal oi steel pins 22from the openings 23 in the tie-down arms 25..

The tie-down arms are welded on the cuter periphery and at oppositesides oi the hood 2l, by means of welds Edo. The tie-down arms 2li areso positioned that they extend below the bottom of the hood in such away as to permit the openings to align themselves with complemensteelpin openings 2E in the locking segments 2S. The locking segments 26 arewelded to the cement head body 2'! by means of welds 26a. The tie-downarms 2d are thus pinned between the segments 2S.

When tl e pin openings in the tie-down arms and the pin openings 25 inthe segments 25 are in alignment, the under surface 29 on thecircumferential bottom rim oi the bonnet or hood 2l is shouldered on theupper surface 3G on the circumferential top rim of the cement head body2T.

The removal of the tie-down pins 22 permits the bonnet or hood 2l of thecement head to be moved upv/'ardly and apart from the cement head body2i. The bonnet or hood 2l may be moved upwardly by attaching a block andtackle (not shown) to the sling 2S positioned on the flexible hose ES.

After the bonnet 2i is removed the collapsible plug le may be placed inthe cementing head the` bonnet may then be replaced, and locked inplace. Of course, lle this operation is takplace, the pump not, isdirected through valve il and flow conduit Se into the casing, and thevalves l' and l? will be in closed position, so that iluid may not flowthrough the cementing head. Bleeder valve fil is provided on theflexible hose line lll for the purpose of releasing the pressureremaining in the cementing head after the new has been directed so as toby-pass the cementing head.

To make safe simple the detaching and attaching of the bonnet or hood 2ito the body 2i of the cementing head, the internal bore surface ofbonnet 2l is made to provide an easy iit by slidable engagement With theouter wall 33 of the cement head body extension t4. In order to preventfluid leakage between members 2l and il', grooves are provided on theinner side walls or" the bonnet 2l, in which grooves are placedresilient sealing rings te. Thus, during the time ings M.

that the pump flow is directed through the cement head, leakage from thehead is prevented.

Since different diameters of casing may be encountered in cementingoperations, it is necessary to make provision for the adaptation of thecementing head to this situation. It is also necessary to make diiierentdiameters of collapsible plug l/-l so that it will fit differentdiameters of casings encountered in cementing wells. In Figures I, IIand VII there is shown a liner or cylinder 3l which is slidably disposedwithin the bore of the cement head body 21. This liner 31 may be made ofany thickness or it may be dispensed with entirely. In this way acementing head may be made of a standard proportion and single size andyet be adapted to diiierent sizes of plugs i4 by the use of thisvariable thickness liner 31.

The means used for segregating fluids in my invention is the typicalcollapsible cementing plug |43. Plug Ma is of exactly the sameconstruction as plug lll, and when plug I4 is described, suchdescription will also apply to plug Elia.

This plug I4 is merely a preferred form, and may be made in a variety ofshapes and sizes. This collapsible plug is made of resilient material,such as rubber, natural or synthetic, which has a yielding nature, andyet is capable of withstanding considerable abrasive action. This plugmay be used to segregate any of the iluids used, or encountered, in thecementing operation, such as cementing slurry, Well fluid, water orother fluids.

The typical collapsible plug I4, shown in the drawings, is substantiallyin the form of a spool, having flanges 33 on the outer periphery thereofwhich produce sealing action when these ilanges are made to contact thewalls of the bore 0f the well pipe. It has an irregular axial opening 39which constitutes a hollow internal bore. At each end of the plug,ferrules 40 and Alia are inserted, and are retained inside oi the endsof the plug by means of rmly secured wire bind- The ferrules areprovided with threads d2 on their inner surfaces, which threads provideattaching means for the closure member 43, extending member d4, or othermembers. A cork or other stopper may also be inserted in the end of theferrule.

Before injecting the plug I4 into the well casing, the opening throughierrule Il@ is sealed by threaded engagement therein of closure plug 63,and the hollow bore 39 of the plug is filled with water or othernon-compressible iiuid. To maintain the fluid within the plug while itis positioned in the cement head, and so that no air will be trappedtherein, the lower ferrule :lila is sealed with the cork or stopper 0.5.

The plug I4 is so constructed that it may be deformed to the contours ofthe casing, or passageway in the casing, through which it is forced bypressure; and it will reform itself to the contours of the casing, orother passageway, after passing through any constriction in the casing.When the plug is deformed by being 'forced through a constriction, thesealing cork t5, which is used to retain the duid inside the plug, maybe ejected from the plug by reason of the fluid pressure against it frominside the plug, so that the nuid inside the plug will be partially orWholly discharged therefrom. After the constriction has been passed theplug reforms itself to its original shape.

Plug I 4, when confined under pressure, has

all of the attributes of a solid. It is made of resilient material, sothat it may be elongatedV for passage through a restricted area, or itmay be reduced in diameter by the ejection by pressure of iiuidtherefrom, to pass such restricted. area. The rigidity of the plug isregained alter passing the restrictedL area. This so because a hydraulicsuction built up inside the plug, which suction by the ejection bypressure of the plug when passing the restricted area. This hydraulicsuction, acting in conjunction with the reilex action of the resilientmaterial of which 'the plug is made, causes the plug to resume itsoriginal shape after p ing the restriction; and in reconorming itself,liquid from the surrounding area, equal volume to that discharged, willbe drawn into the hollow space inside the plug by the force ol thelayciraulic suction. Thus my plug, being of substantially rigidcharacteristic, notwithstanding its non-rigid elements, e-rective asmeans for substantially sealing oi and separating the contents of a wellconduit, or other conduit, at whatever places or intervals may bedesired.

ln Fig. Il is shown the collapsible plug i4 in position in the cementhead preparatory to being inducted into the well casing by pressureapplied by the surface pumps. This primary plug, as shown in Fig. II, isused for the purpose or spacing the cementing slurry which follows itand the well fluid which precedes it. This plug it is placed in thecement head in the manner hereinabove described while the well is beingwash-circulated.

Alter the well has been waslncirculated to the satisfaction of theoperator, Valve ii is closed and valves i2 and l are opened so that theflow circuit will be directed through the cement ing head Si.

The plug valve i has a central opening iii through the key et, whichopening is shown in closed position in Figures I and II. When the valvekey [lli is partly rotated by a wrench or other means, the valve openingit is caused to register with the lower opening ol the valve l, whichleads into the casing, and opening it will then communicate with theinterior of cementing head il, wherein plug is is positioned.

ln order to maire the valve l easier to open, there has been provided aby-pass between the lower part of the cement body i and the casing belowthe valve l. This bypass arrangement consists o a small diameter pipeconnected with proper nipples, with a valve Si! thereon, which whenopened, will allow the equalization of the pressure in cement head d andthe casing below the valve rihus, the valve l will be sier to open whenthe pressures on each side or its closed key are equalized.

lifter the pumping flow is directed through the cement head in themanner hereinabove described, the pressure from the surface pumps isincreased and plug lll is forced through the central opening it in valvel, and into the bore of the casing. The increased pressure from thepumps is necessary, because the opening 46 is of lesser diameter thanthe plug I4. The cork @5 may be forced out of ferrule opening lilla whenplug Ill is forced through opening 46. The operator may tell when pluglll has passed the opening l5 by the pressure drop on the surface pump.

Alter the plug it has passed the valve l and has proceeded into thecasing, the Valves l2 and l are closed (alter opening valve Il) so thatthe pumping flow will again by-pass the cement head 6. This is done inorder that the bonnet 2| of cement head li may be removed in the mannerhereinabove described for the placement therein oi collapsible pluglila, with its connecting extension fifi and check valve lil attachedthereto; and this operation is performed without interrupting thepumping operation or without removing the cement head from its attachedposition on the casing string.

After the collapsible plug l@ has been forced by pressure into the Wellcasing, in the manner hereinabove described, the cenienting slurry orother well bonding material is pumped into the well casing through valveil and pipe tu, alter valves and l' are closed. This cementing slurryfollows the plug le, and plug ill segregates the well fluid ahead of itfrom the cementlng slurry or other bonding material which follows it.

ln Fig. Ill the primary collapsible plug lit is shown at the bottom olthe well casing, and immediately above it in the casing is shown thecement slurry lll. Fhe volume ol' slurry introduced into the well casingis determined by the operator to suit the particular needs oi' thecementing job to be performed.

While the cementing slurry lil is being pumped into the well casing thehood 2i on the cement head ti is removed and collapsible plug lea isinserted into the cement head in the same manner that collapsible plug lwas inserted therein. Plug la is exactly the same in construction asplug lil. Attached to the top or" collapsible plug lila is the checlavalve 5i. The plug Ilia and check valve 5i are connected by means of theextension member lrl. Extension member is a rod which has threads oneach end thereof so that it can be screwed into the check valve lil bymeans of threads ll in the lower end thereof, and the other end of theextension rod ifi can be screwed into the threads i2 on the inside or"the ferrule dit in the upper end of collapsible plug Illa.

when the desired amount of cementing slurry has been pumped into thewell casing, valve il is closed, after opening valves l2 and. l, so thatthe pump flow will be again directed through the cement head li.Pressure is applied to the plug lila so that it is forced through theopening fili of valve l in the same manner that plug ifi was forcedtherethrough. rlhe valve hl, being of less diameter than the openingfili, will follow the plug ifea through the opening fili. rl'he plugElia then segregates the cementing slurry lll from the well fluid, orother fluid, which follows the plug lila in the bore or the well casing.

After the plug ita and check valve 5l have entered the casing, valve ilis opened and valves I2 and 'i are closed so that the pumping now willagain oy-pass the cement head il.

Any number of spacer plugs may be injected into the well casing tosegregate any number or any kinds or" iiuids, as may be required ordesired, in the manner hereinabove described. These spacer plugs may beinjected into the well casing without stopping the pumps and withoutinterrupting the ilow through the well circuit.

In Fig. III the plug l is shown at the bottom of the casing after valveassembly i5 of float shoe Il has been ejected therefrom. Immediatelyabove the plug ifi is the cementing slurry, and immediately above thecernenting slurry is the collapsible plug Isa with check valve 5lattached thereto.

.es the pressure flow is continued from the ll surface pumps, and thefluids continue to iiow in the well circuit, the plug I4 will be ejectedfrom the bottom of the casing, as shown in Fig. IV, thus allowing thedischarge of the slurry from the casing into the well bore.

As plug Ma progresses downwardly in the casing it will bepressure-collapsed through the stall collar 5 and will reconform itselfto the walls of the casing bore below the stall collar 5. Check valveEl, being attached to the collapsible plug 14a, will be forced tostopped position in the stall collar 5, thus building up pressure on thesurface pumps and preventing the further flow of fluids within the wellcircuit.

Fig. V1' shows the check valve 5l in locked position in the stall collarwith the collapsible plug Illa having passed the stall collar andconformed itself to the contours of the casing 3.

As shown in detail in Fig. VI, my stall collar 5 has a truncated inlet52 and also has a truncated outlet 5t which inlet and outlet are joinedat their smallest diameters by throat 54. This construction, as shown,forms a Venturi-like passage through the stall collar. The uppertruncated inlet 52 also provides a seat and stop for the check valve 5i.The check valve 5l has a taper 52a near its upper end, which taper 52amates with seat 52.

A groove is recessed into the inner surface of the truncated outlet 53,which groove extends downwardly with the vertical axis of the stallcollar 5 from the smallest diameter of the said truncated outlet 53, anda top shoulder 55a is thus provided at the top of this recess 55. ThisVen turi-like flow passage is constructed of a cylindrical tube 55,which tube is detachably engaged with the outer body 51 by means ofthreads 5S, which are made secure to complementary body threads 59.

The inner wall of the body 51 has a greater interior diameter below thethreads 59 on body 51, which construction is so provided to permit anextremely easy and slidable t, when screwing the tube 55 to body 51, inassembling the stall collar 5.

At the lowermost point on the rim of tube 55 there is providedhorizontal plane surface 6i to shoulder on a complementary horizontalplane surface 62, provided on the top rim of the stall collar extensionnipple 63.

The extension nipple 53 is connected by male threads 64 to lower femalethreads $5 on the body 51. The bearing provided by the shoulders El and52 is so constructed that the greatest possible support will be suppliedto the tube 55 after it is mounted within the body 51. To furtherstrengthen this support, extension nipple 53 is integrally attached by asuitable weld 56 to the lowermost point of the body 51. The extensionnipple 63 has a male lower thread 61 for attachment to a complementarythread 63 within a coupling of the well casing string 3. It is to benoted that the bore S9 of the extension nipple s3 has the same diameteras the bore of the casing string 3, on which the stall collar ispositioned.

As the collapsible plug lila progresses downward with the flow streaminside of the well casing, by reason of pressure applied by the surfacepumps from above, it reaches the Venturi-like passage inside of thestall collar 5, and the pressure from the pumps deforms it and forces itthrough the throat 54 in the stall collar.

rihe operator will know when the check valve 5l reaches the stall collarby the sharp pressure rise on his pumps. When check Valve 5l reaches itsseating position in the stall collar, it will be forced into lockedposition.

The check valve 5l is so constructed that the top thereof is tapered insuch a way as to seat on the truncated inlet 52 of the stall collar tube5S. It is made of some drillable material, preferably of aluminum, andis rigid enough that it will not be forced through the stall collar inthe manner that collapsible plug Ilia is forced therethrough.

On the lower end of check valve 5E there is an expansible split ring'52, which is contracted when the lower end of the check Valve 5l isforced by pressure through the throat 54 of stall collar tube 55. Whenthe split ring passes the shoulder 55a it will relax and snap intolocking position in the groove 55. On the outer wall of the check valve5l are sealing rings 53, which are for the purpose of preventing leakageof fluids around said check valve 5l after it has been locked inposition.

When the check valve 5l is in locked position in the stall collar, itcannot be forced downward because the top thereof is firmly seated inthe upper part of the stall collar tube 55, and it is prevented frommoving upward because it is locked in position by the split ring 12underneath the shoulder 55a.

When the check valve 5l is in such locked position, the surface pumpswill be stalled, and the flow in the well circuit will be immediatelystopped. Fluid is prevented from flowing back into the well casingthrough the stall collar when the pressure is released from the surfacepumps, because the check valve 5l is prevented from moving upward byreason of its being locked in place by the split ring 12. Thus, there isprovided an immediate shut-0H of fluid being discharged from the wellcasing, and an immediate shut-off of fiuid flowing back into the wellcasing. All fluid is then static.

The stall collar tube 5S, the check valve 5l and extension member ad arepreferably made of a drillable material, such as aluminum, so that afterthe cement is set around the casing, these elements may be drilled out,for the purpose of producing oil through the casing, and also for thepurpose of deepening the bore of the well, if so desired. Of course, thecollapsible plugs I4 and Ilia, being made of rubber or other resilientmaterial may be drilled out also.

When check valve 5| reaches the truncated opening 52, it is necessary toincrease the pump pressure in order to force it into locked and seatedposition in the stall collar. This increased pressure, however, is notapplied to any collapsible spacer plugs used in my method, because thepressure is absorbed by the check valve 5 and stall tube 56. The members5l and 56 in effect constitute a baille to absorb the pressure from thepumps. This is important because the increased pressure, if applied ltothe collapsible plugs, would cause their distortion and allow leakagearound them, with the result that there would be some mixing of fluidssegregated by the plugs. My device prevents such leakage and rmxing.

ln the function, operation and practice of my invention the string ofcasing is progressively made up as it is guided and floated into thewell bore. The float shoe fl, with the valve assembly l5 mountedtherein, is first mounted on the lower end of the first joint of casing.Then the stall collar 5 is placed in position between the rst joint ofcasing and the string of casing above it. This stall collar 5 may beplaced at any interval along the casing as desired by the operator; but

13 in practice it is desirabley to space it a shortdistance above thefloat shoe d.

After the casing, with its appurtenant float shoe and stall collar, hasbeen guided and floated into the hole to the proper depth, the trip balllt is dropp to the casing and allowed to gravitate tou .d thel bottomthereof,V Trip ball MS is small enough to pass the throat '5ft or" thestall collar but it will come to rest on .the shoulder |'i in the ioatshoe i.

After this operation, the cement head which has already been assembled,with flexible hose l t attached thereto, is placed in position at thetop of the casing t by means of a suitable casing oonnecting collar tu.The flow line i3d, from the surface pumps is conn-.cf f TlS. and thenthe cementing assembly is ready for operation.

The nrst step in ceinenting the casing in the Well is to wash-circulatcthe hole. In order to have a full and unrestricted flow oi fluidsthrough the well new circuit during this wash--circulating period, it isdesirable to eject the valve assembly |55 from the float shoe l beforethis operation begins. The trip ball it has already come to rest on thetaper or shoulder and when pressure is applied from the surface pumpsthrough valve ll and now line da and thence through the cas ing fi, tothe trip ball lli, the pressufe will cause shear screws i9 to be shearedor?, and then the valve assembly it will be ejected from the float shoebody Siti into the bore of the well, as shown in Figures Il, III and IV.There will then be an unrestricted passage through the casing bore forthe circulation of Fluid through the well new cir cuit.

After the well has been wash-circulated to the satisfaction or" theoperator, a collapsible plug |11 is put into the casing under pressureby directing the well flow circuit through the cement head Ei by openingvalves i2 and l and closing valve il. Prior to this operation thecollapsible plug ifi has been positioned in the cement head E byremoving the bonnet 2| from the cement head il, placing the plug Hl inthe head as shown in Figure II, and then replacing the bonnet 2i. Thiswas done without interrupting the now in the well circuit, becauseduring this operation the r'low has been directed through valve l i andflow line to. into the casing while Valves l 2 and "l were f closed.

After the collapsible plug it has been forced by pressure through theopening il of valve i and has proceeded into the casing below the cementhead 5, then valves i2 and i are closed and valve opened so that theflow is again directed in such a way as to by-pass the cement head E.Without interrupting the continuity of flow the cementing slurry 'iti ispumped into the well cas-- ing behind the collapsible plug M.

While the cementing slurry is being run into the well casing, bonnet 2|on the cement head 6, is again removed and the collapsible` plug itawith check Valve 5| attached thereto is positioned in the cement head t,in the manner shown in Fig. VII. The bonnet 2| is replaced and, after asufficient amount of cementing slurry has beerun into the well casing,valve ll is closed ai ter valves l2 and 7| are opened., so that the newwill again be directed through the cement head t, and pressure from thesurface pumps is applied to the collapsible plug Nia.

Collapsible plug Ma, carrying the check valve 5|, is forced by pressurethrough valve and into the casing in the same manner that plug |4- Wasintroduced into the casing. After plug Illa and check valve 5| haveentered the casing, the flow is again directed through valve I| and flowline 5a into the casing, and the cement head 6 is bypassed by closingvalves |2 and i.

The pumping is continued and plug lila, carrying check valve 5l, isforced through the casing with the well fluid. Plug ita acts as a spacerbetween cementing slurry l@ and the well uid behind plug ma, in themanner shown in Fig. III, wherein plug ma is shown during the time it isprogressing downward in the casing, and plug i4 is at the lower end ofthe casing but not yet ejected.

As the flow continues on its path from the surface storage facilitiesthrough the pumps, through the casing, into the well bore, and upwardaround the casing and back to the surface storage facilities, the plugil will be ejected from the bottom of the casing and the cementingslurry 'm will be discharged into the well bore as shown in Fig. IV.IrEhe plug Hin is forced by pressure through the Venturi-likerestriction inside of the stall collar 5, and valve 5| is forced intoseating position in the stall collar 5, in the manner shown in detail inFig. VI, and as has been described in detail hereinabove.

When Valve 5| is locked in position, it will cause the surface pumps tostall and the operator will immediately know that the cementing job hasbeen completed, and he will stop the pumps and release the pressurethereupon. The valve 5| is locked by means of locking ring 'Eli so thatit may not be forced upwardly in the casing by the iiuid head pressureof the cementing slurry outside of the casing, and will not allow thecementing slurry to llow back into the casing above the stall collar.Thus, there is an immediate and automatic stoppage of the now of fluidin the Well circuit, in both directions, when valve 5| is brought intolocked and seated position.

The collapsible spacer plug il may be used for the segregation of anytype or hind or nurnber of fluids used during a cementing operation; andas many or the plugs may be inserted into the well, in the mannerhereinabove described, as may suit the convenience and desires of theoperator.

After the cementing job has been completed, and the cement has set, thevalve 5|, connecting member til, stall collar tube t5, plug it and plugMa may be drilled out, in order to make the bore of the casing free ofobstructions for the winning of production therethrough.

It is to be emphasized that the procedure outlined above for thepractice o1 my invention is a continuous and uninterrupted operation. Atno time during the cementing operation is the pressure released from thepumps until the ce inenting job is completed. During this procedurerestrictions are removed from the well casing and there is provided afree, continuous and unrestricted flow or" fluids through the wellcasing to the greatest extent possible.

Various changes and adaptations may be made in the practice of myinvention without departing therefrom. For instance, the central openingthrough the removable assembly i5, in iloat shoe ll, may be permanentlyclosed by a plate, replacing the valve seating element il, which platemay be threaded or welded in place, across said opening. In this waytrip ball may be dispensed with, and pressure applied diV rectly to theplate to eject assembly l5 from the shoe.

Also, the float assembly valve may be provided with a plurality of valveseats to accommodate a plurality of float balls, thus to make multiplecheck valves in this assembly when desired.

My invention as disclosed herein is primarily intended for the cementingof a string of casing at the lower end thereof. However, it is to beunderstood that my invention, and the method thereof, and the practicethereunder, may be used as the lower stage cementing step of amulti-stage cementing operation.

By multi-stage cementing it is meant that provision is made for thedischarging of cementing slurry into the well bore in divided batchesand at selected elevations or levels along the well pipe. A typicalmulti-stage cementing operation is disclosed in my co-pendingapplication, Serial No. 690,969; and the present invention may be usedwith the system shown in said co-pending application.

To use the invention disclosed herein in a multi-stage cementing job, mystall collar and check valve unit would be eliminated and the float shoeonly is used, which float shoe would be positioned for its customaryfunction at the lower extremity of the well pipe. On the well pipe abovethe shoe, the multi-stage collar or collars would be positioned at theproper points.

rihe continuous flow and uninterrupted pumping, as is made possible bythe instant invention, and the provision for the positive segregation offluids during the cementing operation, and the elimination of dowrestrictions in the Well casing, are particularly adapted for use inmulti-stage cementing because it is desirable in such multistagecementing to segregate the various quantities of fluids used in thecementing operation and that there be continuous and unrestricted flowthrough the well pipe during the operation.

When the terms cementing slurry or slurry are used herein, the terms aremeant to include any fluid of a cementitious nature used to bond wellpipe in a bored hole, whether it be plastic, cement or other materials.

From the foregoing it is apparent that I have invented an apparatus forguiding, floating and cementing well casing in the bore of a Wellwherein full and unrestricted flow of uids through the well casing isattained; there is continuous flow of fluid through the well ow circuit;as many and dierent kinds of fluids as may be desired in the cementingoperation are segregated without stopping the flow of fluids through theWell flow circuit, and without releasing the pressure from the wellcasing; a positive and immediate closure of communication between thewell casing and the bore of the well is attained by pressure, but whichpressure is not applied to the fluid segregating media; with the resultthat the causes of costly cementing failures in the past have beeneliminated, and a safe, speedy, positive and entirely dependable systemintroduced into the well cementing art.

I claim:

l. In a device for cementing well casing in the bore of a well, acollapsible plug made of resilient material having a circumferentialsurface on the outer periphery thereof engageable with the inner wall ofthe well casing when the plug is in normal undeformed condition, saidplug having a hollow internal bore and being provided With an opening ineach end thereof communieating with said bore, which openings areadapted to receive closure members; a non-compressible fluid occupyingsaid hollow internal bore; closure members initially disposed in saidopenings so to confine said fluid, one of which closure menibers isadapted to be expelled from its opening whenever the plug is initiallymaterially deformed by pressure applied thereto, whereby, some fluid maybe expelled from the internal bore of said plug and some fluid may bedrawn back into said bore when the plug assumes its original shape.

2. In a device for guiding, floating and cementing well casing in abored hole, a tubular body adapted to form a part of a weil casingstring; a detachable tubular member mounted Within the body, saidtubular member being substantially Venturi-shaped, and having a recessat its lower end adapted to receive a relaxed split ring, and having avalve seat at its upper end; a valve head arranged to enter said memberand rest on said seat to effect a valve closing the passage through themember; and a split ring carried by said head and arranged to expandinto said recess and lock the valve in closed position.

3. In a device for guiding, floating and cementing well casing in abored hole, in combination, a valve member comprising an elonga"edcylindrical body having a taper at the upper end thereof; a split ringon the lower end thereof; a resilient collapsible spacer plug having aplurality of flanges on the outer periphery thereof and a hollowinternal bore, and threaded openings in the ends thereof; and anelongated connector member adapted to join the body member with thecollapsible plug by screwing one end thereof into the bottom of the bodymember and the other end thereof into one end of the collapsible plug.

In a device for guiding, noating and cementing Well casing in a boredhole, a tubular member having a tapered seat in its upper part and ashoulder in lower part, said member lelng arranged for incorporationwithin a string of casing; a valve member comprising an elongatedcylindrical body having a taper at the upper end thereof adapted to matewith said tapered seat and thus provide closure of the well casing; asplit ring arranged on the lower end of said body and adapted to relaxunderneath said shoulder at the time of closure of the well casing, andthus prevent the body from moving upwardly in the casing.

5. In a device for guiding, floating and cementing well casing in abored hole; a string of casing; a float shoe carried on the lower end ofsaid casing; a neat valve assembly frangibly mounted in said oat shoeand adapted to be ejected therefrom by pressure; a stall collar disposedon said string of casing in spaced relation with said shoe, the interiorof said stall collar being adapted to receive and loci: in place a checkvalve to stop the iiow of fluids through casing string; a check valveadapted to seat and be locked in place inside said stall collar bypressure applied thereto; a plurality of collapsible spacer plugsadapted to provide segregation between the fluidsused in cementing thewell casing in the bored hole, and adapted to move with the fluid insidethe casing; a plug valve; a valved conduit; a cementing head having aremovable hood thereon, said cementing head being adapted to communicatewith the well casing through the plug valve and with fluid circulatingpumps through the valved conduit; whereby said collapsible spacer plugsmay be injected into the well casing without releasing the pressure fromthe fluids in the casing and without removing the cementing headassembly from the top of the casing; and means for admitting fluid underpressure into the well casing and around it.

6. In a device for guiding, floating and cementing a well casing in abored hole, a resilient collapsible spacer plug having a hollow internalbore and being provided with an opening at each end thereofcommunicating with said bore and having a circumferential surface on theouter periphery thereof engageable with the inner wall of the Wellcasing when the plug is in normal undeformed condition; and insertablemembers closing said openings, one of which members is expellable bypressure of liquid contained in the plug when the plug is initiallydeformed.

7. In a device for cementing well casing in the bore of a well, acollapsible plug made of resilient material, said plug having a hollowinternal bore and being provided with an opening at each end thereofcommunicating with said bore and having a circumferential surface on theouter periphery thereof engageable with the inner Wall of the wellcasing when the plug is in normal undeformed condition; and a closuremember inserted in each such opening,

8. In a device for cementing Well casing in the bore of a well, acollapsible plug made of resilient material, said plug having a hollowinternal bore and being provided with an opening at each end thereofcommunicating with said bore and having a circumferential surface on theouter periphery thereof engageable with the inner wall of the wellcasing when the plug is in normal undeformed condition; a closure memberinsertable in one of said openings and adapted to be expelled bypressure of liquid contained Within the plug when the plug is initiallydeformed; a closure member removably afliXed in the opening at the otherend of said plug, said closure member providing a connector between saidplug and a device to be conveyed thereby through a conduit.

9. In a device for guiding, floating and cementing well casing in abored hole, a tubular body adapted to form a part of a Well casingstring; a tubular member mounted Within the body, said tubular memberhaving a recess at its lower end and adapted to receive spring actuatedretainer means, and having a valve seat at its upper end; an imperforatevalve head arranged to enter said member by hydraulic pressure and reston said seat to effect a valve closing the passage through the memberagainst the ow of fluid in either direction; and spring actuatedretainer means carried by said head and arranged to expand into saidrecess and lock the Valve in closed position.

10. In a device for guiding, floating and cementing well casing in abored hole, a tubular body adapted to form a part of a well casingstring; a tubular member mounted within the body, said tubular memberhaving a recess at its lower end adapted to receive a relaxed splitring, and having a valve seat at its upper end;

an imperforate valve head arranged to enter said member by hydraulicpressure and rest on said seat to effect a valve closing the passagethrough the member against the flow of fluid in either direction; and asplit ring carried by said head and arranged to expand into said recessand lock the valve in closed position.

SYLVESTER B. SCHNI'ITER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,011,484 Perkins et al Dec. 11, 1911 1,662,311 Hamer Mar. 13,1928 1,735,330 McMahan Nov. 12, 1929 1,743,626 Shaver et al. Jan. 14,1930 1,849,190 Jackson Mar. 15, 1932 2,107,327 Creighton Feb. 8, 19382,167,747 Dyer Aug. 1, 1939 2,196,652 Baker Apr. 9, 1940 2,196,657 BurtApr. 9, 1940 2,236,987 Bechtold Apr. 1, 1941 2,286,126 Thornhill June 9,1942 2,295,822 Armentrout Sept. 15, 1942 2,330,267 Burt et al Sept. 28,1943 2,330,659' Anderson Sept. 29, 1943 2,352,744 Stoddard July 4, 19442,370,833 Baker Mar. 6, 1945

